Tri band BPF using stub loaded new stepped impedence resonator

A compact microstrip tri band BPF using stub loaded new stepped impedance resonator is proposed in this paper. Presented filter is compact in size, simple and easy to fabricate. By tuning the length of stub the frequency of passband filter is controlled but the frequency of first passband is not changing. The BPF achieved insertion loss of 0.7, 0.6 and 0.8dB at 1.8, 4.18 and 5.52GHz respectively and the return loss is below 17dB. In the Proposed filter miniaturization is achieved with size of 0.25 λ g × 0.08 λ g HFSS tool is used for the simulation of proposed filter.